aws integrator #8

  • By containers
  • Latest version (#8)
  • xenial, bionic
  • Stable

Description

This charm can grant select permissions to instances of applications
related to it which enable integration with AWS specific features,
such as ELB, EBS, etc.


Overview

This charm acts as a proxy to AWS and provides an interface to apply a
certain set of changes via IAM roles, profiles, and tags to the instances of
the applications that are related to this charm.

Usage

When on AWS, this charm can be deployed, granted trust via Juju to access AWS,
and then related to an application that supports the interface. The set
of permissions that the related application could request is documented in the
interface's Requires API documentation.

For example, CDK has support for this, and can be deployed with the
following bundle overlay:

applications:
  aws-integrator:
    charm: cs:~containers/aws-integrator
    num_units: 1
relations:
  - ['aws-integrator', 'kubernetes-master']
  - ['aws-integrator', 'kubernetes-worker']

Then deploy CDK using this overlay:

juju deploy cs:canonical-kubernetes --overlay ./k8s-aws-overlay.yaml

The charm then needs to be granted access to credentials that it can use to
setup integrations. Using Juju 2.4 or later, you can easily grant access to
the credentials used deploy the integrator itself:

juju trust aws-integrator

To deploy with earlier versions of Juju, or if you wish to provide it different
credentials, you will need to provide the cloud credentials via the credentials,
charm config options.

Permissions Requirements

The credentials given to the charm must include the following access rights:

EC2
AssociateIamInstanceProfile
CreateTags
DescribeInstances
IAM
AddRoleToInstanceProfile
AttachRolePolicy
CreateInstanceProfile
CreatePolicy
CreateRole
DeleteInstanceProfile
DeletePolicy
DeleteRole
DetachRolePolicy
ListAttachedRolePolicies
ListInstanceProfiles
ListPolicies
ListRoles
RemoveRoleFromInstanceProfile
CreatePolicyVersion
ListPolicyVersions
GetPolicyVersion
DeletePolicyVersion
SetDefaultPolicyVersion
GetPolicy
STS
GetCallerIdentity

Note that these may be different from the permissions that Juju requires to operate.

Resource Usage Note

By relating to this charm, other charms can directly allocate resources, such
as EBS volumes and ELBs, which could lead to cloud charges and count against
quotas. Because these resources are not managed by Juju, they will not be
automatically deleted when the models or applications are destroyed, nor will
they show up in Juju's status or GUI. It is therefore up to the operator to
manually delete these resources when they are no longer needed, using the
AWS console or API.

Examples

Following are some examples using AWS integration with CDK.

Creating a pod with an EBS-backed volume

This script creates a busybox pod with a persistent volume claim backed by
AWS's Elastic Block Storage.

#!/bin/bash

# create a storage class using the `kubernetes.io/aws-ebs` provisioner
kubectl create -f - <<EOY
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: ebs-1
provisioner: kubernetes.io/aws-ebs
parameters:
  type: gp2
EOY

# create a persistent volume claim using that storage class
kubectl create -f - <<EOY
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: testclaim
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 100Mi
  storageClassName: ebs-1
EOY

# create the busybox pod with a volume using that PVC:
kubectl create -f - <<EOY
apiVersion: v1
kind: Pod
metadata:
  name: busybox
  namespace: default
spec:
  containers:
    - image: busybox
      command:
        - sleep
        - "3600"
      imagePullPolicy: IfNotPresent
      name: busybox
      volumeMounts:
        - mountPath: "/pv"
          name: testvolume
  restartPolicy: Always
  volumes:
    - name: testvolume
      persistentVolumeClaim:
        claimName: testclaim
EOY

Creating a service with an AWS load-balancer

The following script starts the hello-world pod behind an AWS Elastic Load Balancer.

#!/bin/bash

kubectl run hello-world --replicas=5 --labels="run=load-balancer-example" --image=gcr.io/google-samples/node-hello:1.0  --port=8080
kubectl expose deployment hello-world --type=LoadBalancer --name=hello
watch kubectl get svc -o wide --selector=run=load-balancer-example

Configuration

snap_proxy
(string) HTTP/HTTPS web proxy for Snappy to use when accessing the snap store.
snap_proxy_url
(string) The address of a Snap Store Proxy to use for snaps e.g. http://snap-proxy.example.com
secret-key
(string) An IAM secret key. It is strongly recommended that you use 'juju trust' instead, if available.
access-key
(string) An IAM access key. It is strongly recommended that you use 'juju trust' instead, if available.
credentials
(string) The base64-encoded contents of an AWS credentials file, which must include both 'aws_access_key_id' and 'aws_secret_access_key' fields. This can be used from bundles with 'include-base64://' (see https://jujucharms.com/docs/stable/charms-bundles#setting-charm-configurations-options-in-a-bundle), or from the command-line with 'juju config aws credentials="$(base64 /path/to/file)"'. It is strongly recommended that you use 'juju trust' instead, if available. This will take precedence over the 'access-key' / 'secret-key' config options.
snapd_refresh
(string) How often snapd handles updates for installed snaps. The default (an empty string) is 4x per day. Set to "max" to check once per month based on the charm deployment date. You may also set a custom string as described in the 'refresh.timer' section here: https://forum.snapcraft.io/t/system-options/87